1. Field of the Invention
The present invention relates to a method for calibrating an instrument used to analyze particles, and more particularly, concerns a method and materials for calibrating flow cytometry instruments prior to using such instruments for obtaining at least one light-related signal from particles passing through the instrument.
2. Background Description
There are a number of commercially available instruments used for particle or cellular analysis. Characteristics of particles, particularly biological particles or cells, may be determined by techniques in which the particles remain relatively fixed while being analyzed or while the particles are moving in a stream or carried in a suspension. Flow cytometers are known and available for analyzing or detecting certain characteristics of particles which are in motion. In typical flow cytometry instruments, cells or other biological particles are caused to flow in a liquid stream so that each particle, preferably one at a time, passes through a sensing region which measure physical or chemical characteristics of the particles. Although a variety of signals may be detected for association with different characteristics of the particles, including electrical, acoustical and radioactive, flow cytometers commonly rely on opticald. Instead of monomers 1a and 2a, 61.1619 g (0.28706 mol) of monomer 1b is dehydrochlorinated in an "initial" solution of 338.4 g PPA having a P.sub.2 O.sub.5 content of 77.2% (prepared by mixing 101.5 g of 85.4% H.sub.3 PO.sub.4 with 236.8 g of 115% PPA). When dehydrochlorination is substantially complete, 69.5488 g (0.28706 mol) of monomer 2j is added followed by the gradual addition of 140.1 g of P.sub.2 O.sub.5. The mixture is then stirred and heated essentially according to Example 8. The amount of P.sub.2 O.sub.5 is preselected (as determined in accord with the aforementioned formulae a* and b*) to provide the reaction mixture with an effective P.sub.2 O.sub.5 content of approximately 83.8% prior to the start of polymerization and an effective P.sub.2 O.sub.5 content of approximately 82.2% subsequent to substantial complete polymerization. The reaction product obtained exhibits stir-opalescence and is further characterized as having a polymer concentration of 17%; fibers are readily formed by direct spinning, or drawing from the reaction product. The polymer obtained is of the following structure: EQU --AB--.sub.n
characterized by an intrinsic viscosity of 16 dL/g in MSA at 30.degree. C. which corresponds to an n value of average polymerization of about 60.